Fungi facts

• widely distributed in nature

• about 400,000 species

• facultative anaerobes or strict aerobes. none are obligate anaerobes

• get nutrients by absorption

Typical mold growing up into the air. conidiophore, which holds the conidia, is the reproductive form of molds in nature

Fungi are ubiquitous

• most common organisms in the air that we breathe

• we are all exposed to fungi on a daily basis

• those who live in a moldy environment are more exposed than others

• fungi are not spread person-to-person because they don’t form spores in tissue

Fungi are eukaryotes

• 80s ribosomes

• sterols

• bound organelles

• multiple linear chromosomes

Fungal nutrition

• they grow into their food

• they live on dead organic matter and secrete enzymes that break down complex carbohydrates/proteins

• do not photosynthesize

Fungal cell wall

• glucan: β- (or α-) linked glucose

• mannan: α-linked mannose

• chitin: β-linked N-acetylglucosamine

Layers of the candidal cell wall

• most prominent layer of the candidal wall is mannoprotein

• underneath, glucan, then glucan-chitin, another mannoprotein layer, and finally the plasma membrane

Membrane

• primary sterol is ergosterol rather than cholesterol

• this difference is the basis for two classes of antifungal drugs

  • amphotericin B

  • imidazoles

Category: Microbiology Notes